Carburetor structure



Nov. 17, 1942. 1. E. COFFEY 2,302,527

CARBURETOR STRUCTURE Filed July 25, 1940 FIG.1.

INVENTOR IRVEN E. COFFE Y FIG.4."

ATTORNEY Patented Nov. .17, 1942 cAaBURE'roa STRUCTURE Irven E. Coffey,Normandy, Mo., asslgnor to Carter Carburetor CorporatiomSt. Louis, Mo.,V a corporation of Delaware' I Application July 25, 1940, Serial No.347,415'

' 7 Claims. (Cl. 261 -39) This invention. relatesto carburetors forinternal combustion engines and consists partic-- ularly in novel meansincorporated in an automatic choke carburetor for indicating to .the

operator the point in the throttle opening movement when the usualthrottle operated unloader mechanism is about to become effective toopen the choke valve.

During cold starting of an automobile engine,

thechoke valve is normally closed and the throttle valve partly open. Incase the engine should become loaded due to the drawing of excessivegasoline into the cylinders, it is neces-.- sary to open the chokevalve-and turn over the engine a few times in order that this excessivefuel may be swept out of the cylinders. This unloading is usuallyaifected through a connection to the throttle valve which positivelyopens the choke valve when the throttle is substantially fully opened.

There has been a tendency to provide for enare attained substantiallyby'the structure illustrated in the accompanying drawing in which:

Fig. 1 is an elevation of .an automobile carburetor showing theinvention applied thereto,

parts being sectioned for clearer illustration.

Fig, 2 is an elevational view showing certain parts of the structure inFig. 1, but with the choke valve closed.

Fig. 3 is a view similar to Fig. 2 but showing the choke valve closedand thethrottle valve partly opened to its starting position, and

Fig. 4 is a view similar to Figs. 2 and 3 but showing the throttle valvefully opened and the choke valve in its unloaded position.

ergizin the usual engine selft-starter motor by partial movement of thethrottle pedal. insteadof through the intermediary of a separate pedalor button. Where such unloader" and starting functions are controlled bythe throttle pedal, the driver may inadvertently'depress the pedal farenough during cranking, to force the choke valve open, wherefor it maybe impossible 'to get of the throttle valve.

Another object is to provide means for rendering such additionalindicating resistance ineile'ctive upon still further opening movementof the throttle so that the driver need not, oppose such resistancewhile cranking the engine with the choke in the unloading" position.' v

Still another object is to provide means for freeing the choke valvefrom the indicating mechanism when the throttle has been moved to itsproper starting position so as to facilitate pulsations or breathing ofthe choke valve,

during cranking.

The carburetor shown in Fig. 1 includes a barrel l forming a downdraftmixture conduit and pivotally mounting an unbalanced choke valve 2having a shaft 3, joumaled in the upper por-v tion of the mixtureconduit, and a butterfly throttle valve 4 secured to a shaft 5 joumaledin the lower part of the mixture conduit. At one side of the mixtureconduit, choke-shaft 3 extends into automatic choke control housing 6which contains thermostatic. mechanism for yieldingly closing the chokevalve under cold starting conditions. Suitable automatic choke mechanismis fully described and claimed in Patent No. 2,085,351 issued to thepresent inventor. v

Projecting from the lower part of the mixture conduit adjacent throttlevalve 4 is an inclined housing I slidably receiving an outer plunger 3and an inner plunger 9 telescopingly received in plunger 8. Innerplunger 9 has a projecting stem ID to which is secured a switchcontacting plate II for cooperating with terminal screws that when thethrotle valve is opened to its normal starting position, substantiallyas in Fig. 3,

These objects and other more detailed objects 5;,

contact plate ll engages-screws [2 to energize the starter circuit. Thisstarter switch mechanism is disclosed and claimed in detail in a PatentNo. 2,174,313 issued to the present inventor.

Formed rigidly on choke shaft 3 is a plate l5 and loosely mounted onshaft 3 inside this plate is an eccentric cam element IS. A pintle i1ad.- jacent choke shaft 3 loosely mounts a bell crank l8 carrying ascrew i 9 in one arm thereof for cooperating with cam l6. and having alaterally projecting headed pin 20 at the extremity of its other arm. Alink 2| has a slot 22 in its upper portion whichslidably receives pin 20and, at its lower portion, is pinned at 23 to a crank rigid a recessedportion 21 of the cam is opposite screw l9 and the throttle valve ispermited to close to its normal idling position.

In addition, means is provided for positively opening the choke bysubstantially full opening movement of the throttle valve, as indicatedin Fig. 4. This means comprises an inwardly projecting lip 28, on theupper portion of link 2|, which is positioned to engage a projectingportion 29 on plate l to rotate the choke valve in the openingdirection. By reference to Figs. 3 and 4, it will be seen that thethrottle valve, in its unloading position, as in Fig. 4, issubstantially farther opened than is this valve in its startingposition, as in'Fig. 3. The difiiculty is that the operator may not beable to distinguish, in the operation of the throttle pedal,

between the two throttle positions shown in these following mechanism isprovided: Loosely pivoted on pintle outside of hell crank I8 is aweighted lever element 3| which is normally maintained in theinoperative position, as in Fig. 1, due to its eccentrically weightedlower portion. Element 3| has a finger 32 projecting upwardly therefrom,the finger having an inclined upper edge 33 positioned to be engaged byanoutward lug 34 on choke plate I5, when the choke is closed, to rotateelement 3| slightly in a clockwise direction or, in other words, to itsoperative position. Pivotally mounted on interconnection link 2|,intermediate the ends thereof, is a trigger finger device 35 which isconstantly urged in a counterclockwise direction 'by a spring 36encircling the finger and link 2|. This finger has an inclined upperedge 31 which is disposed toengage an outwardly projecting pin 38 at thelower extremity of element 3|, when this element is moved to itsoperative position, as in Fig. 2, in the patriot finger 3 5, and thethrottle valve is opened substantially to its starting position, as inFig. 3. Upon slight additional opening movement of the throttle, edge 31on finger 35 operates by cam eifect upon pin 33 to rotate element 3|slightly in a clockwise direction' (Fig. 3) and free plate I5 and thechoke I valve from finger 32. Thus, in the starting poon the finger willclear pin 38 and inner edge 39 of the finger will engage the pin,whereupon the mechanical advantage acting against spring 36 will begreatly increased due to the sharp angular change in the inclined planeor camming action. This snap-over action occurs just prior to engagementof choke plate projection 23by lip 28, as indicated by the broken lineposition of elements 23 and 35' in Fig. 3. After the snap-over actionthe parts 35, 36 and 'no longer apply sensible resistance to furtheropening of the throttle and the actual opening of the choke forunloading purposes is effected, after the momentary indication thusafforded, by substantially normal pedal pressure,

Accordingly, it will be seen that I have provided effective means formomentarily indicating to the operator that the throttle valve is openedfar enough for energizing the starter circuit, but without openingthechoke, and further, the mechanism does not effect the choke valve duringthe cranking operation nor does it effect throttle opening'movementunder normal running conditions when the choke valve is fully opened.

The invention may be modified in various respects as will occur to thoseskilled in the art and the exclusive use of all such modifications ascome within the scope of the appended claims is contemplated.

I claim:

1. In a carburetor, choke and throttle valves, yielding means to closesaid choke valve for starting, means operated by an opening movement ofsaid throttle beyond a predetermined position to open said choke valveagainst said yielding means, resilient means connected to said throttleand operatively independent of said choke valve, and a movable abutmentarranged to be moved to a position by the closing .of said choke valveto cooperate with said resilient member to resist the opening of saidthrottle prior to said predetermined position, said resilient memberbeing movable with relation to said abutment after contact therewith bya further movement of said throttle valve beyond said predeterminedposition whereby the resistance to throttle opening movement isdecreased.

2. In a carburetor having a body member,

- choke and throttle valves, a shaft for said choke valve, yieldingmeans to close said choke valve for cold starting, an arm fixed to saidshaft, a shiftable abutment mounted on said body member, means movablewith said choke valve for shifting said abutment into operativeposition, mechanism connected to said throttle and having a part adaptedto contact said arm as said throttle is moved, openward a predetermineddegree whereafter further opening movement of said throttle will causean opening of said choke valve, said mechanism including a springpressed element movable therewith having a steep cam surface arranged tocontact said abutment as said throttle valve is moved openward andbefore said predetermined degree has been reached to provide anindicating resistance to throttle opening, said steep cam surface beingmovable against spring tension out of contact with said abutment bycontinued opening movement of said throttle.

3. In a carburetor having a body member,

choke and throttle valves, yielding means to close said choke valve forstarting, means connected to and operated by an opening movement of saidthrottle for opening said choke valve against said yielding means,mechanism for indicating starting position of said throttle including ashiftable abutment mounted on said body member, resilient meansconnected to said throttle and operatively independent 'of said chokevalve and arranged to cooperate with said abutment when said throttlevalve is opened beyond starting po'- sition to resist such openingmovement, said resilient means being arranged to offer substantiallyreduced resistance when said throttle valve is opened beyond startingposition and means movable with'said choke valve for shifting saidabutment into operative position as said choke valve is moved to aclosed position.

4. In a carburetor. choke and throttle valves, yielding means to closesaid choke valve for starting, means operated by opening movement ofsaid throttle to open said choke valve against said yielding means,mechanism for indicating starting position of said throttle including anelement movable to an operative position by closing of said choke valve,and a resilient device connected with said throttle valve and operableindependent of said choke valve for engaging said element as saidthrottle is moved openward to starting position to yieldingly resistsaid throttle opening movement, said resilient device being movable withrespect to said movable element by continued throttle opening movementbeyond starting position to a position whereby the resistance tothrottle opening is abruptly and sensibly decreased.

5. In a carburetor, choke and throttle valves, yielding means to closesaid choke valve for starting, means operable by opening movement ofsaid throttle valve beyond a predetermined starting sition tomomentarllyresist such throttle opening movement, and arranged to berendered le-s effective by farther opening movement of said throttlevalve beyond said position.

6. In a carburetor having a body member, a choke and throttle valve,yielding means for closing the choke for starting. means connected t)andoperated by an opening movement cf the throttle valve beyond normalstarting position to open said choke valve against said yielding means,mechanism for indicating starting position of said throttle including aspring DYE-879d snap-over device connected with said throttle valve anda depending element carried by said body member, said depending devicebeing positioned by movement of said choke to starting osition forengagement with said snap-over device to momentarily yieldingly resistthe throttle opening movement and means for rendering the throttleresistance less effective, said last named means being operated by acontinued throttle movement.

7. In a carburetor, choke and throttle valves, yielding means to closesaid choke valve for starting, means operated by opening movement ofsaid throttle to open said choke valve against said yielding means,mechanism for indicating the starting position of said throttleincluding an element movable to an operative position by closing of saidchoke, and a spring pressed pivoted member connected with said throttleand operable independent of said choke, said pivoted member including aninclined face for engaging said movable element as said throttle ismoved openward to starting position to yieldingly resist said throttleopening movement, said pivoted member being movable with respect to saidmovable membertby continued throttle opening movement be yond startingposition to a position whereby the resistance to throttle opening isabruptly and sensibly decreased.

' IRVEN E, .COFFEY,

